When I asked my veterinarian, Shinnecock Animal Hospital’s Dr. Kelly Tierney (class of 2014), what she thought about the drug, she paused. “I learned the medications that became my ‘go-to’ drugs from my mentor. He always used an antibiotic in conjunction with clavulanic acid for ailments like urinary tract infections and gastrointestinal infections. So, I’d say newer vets are probably going with clavamox (an antibiotic with clavulanic acid) over amoxicillin, but it’s really your veterinarian’s call.” Depending on your vet’s preference, your cat may currently be on it. Here’s the scoop about amoxicillin for cats.

When is amoxicillin for cats necessary?

A gray cat ready to take a pill from a human. Photography by radleyhebdon/istock.

At one point, amoxicillin was the updated version of penicillin (patented by Bristol-Myers, 1975). It was considered better because it would be active longer, as per PetMD. It’s used in the treatment of cats with infections caused by bacteria, such as wounds (like animal bites), bladder infections, tooth abscesses, eye or ear infections, skin infections and respiratory infections. It can be used on GI infections, but it’s not effective against parasites (like tapeworms). Antibiotics are also usually recommended after surgical procedures, but Cummings Veterinary Medical Center at Tufts University indicates it’s prescribed on a per-case basis.

If your cat’s been in a fight, got a scrape, has itchy ears or runny eyes or he’s scratching like crazy, a trip to the vet will determine the best treatment. Some conditions, like urinary tract infections, are elusive. If your cat starts behaving oddly, especially by urinating outside his litter box, take him to the vet with a urine sample. Chances are he’ll be taking amoxicillin.

Dosing amoxicillin for cats

Follow the timetable. One of the most important things about amoxicillin for cats is to make sure you give the medication at the designated time and for the entire duration it’s prescribed — even if your cat’s symptoms are gone. If you stop the medication before the prescribed end-date, you are making your cat susceptible to an even worse ailment that might be impossible to treat. The World Health Organization states that antibiotic resistance is one of the biggest threats to global health!

Never self-prescribe. Let’s say your cat seems to have an infection similar to the one he had last year and you have some amoxicillin from one of your illnesses in the house. Amoxicillin for cats is not the same as amoxicillin for people. Vetinfo reports it could be toxic to your cat. Confirm every ailment’s origins before treating it. It could be a viral infection, in which case, amoxicillin is useless.

Get a second opinion. If you feel that your cat is taking a lot of antibiotics, and not really improving, go to another veterinarian. Along with a possible misdiagnosis, amoxicillin for cats and other antibiotics come with side effects. So being on them for a prolonged period of time without any improvement could be a red flag that something is wrong.

Potential side effects of amoxicillin for cats

Antibiotics, including amoxicillin, can cause a range of side effects for cats. Since every cat is an individual, each cat will respond differently to amoxicillin. PetCareRX mentions the following as the most prevalent side effects to antibiotics: rashes, fever, kidney or liver damage, diarrhea and vomiting.

Also, antibiotics can be particularly difficult on the digestive system, so confirm if your cat should take amoxicillin with or without food.

In addition, Vetinfo indicates that your cat could have dangerous complications if amoxicillin is taken while other antibiotics are in his system. And some cats are allergic to it. Monitor your cat closely while taking any medications, and alert your vet to anything out of the ordinary — health or behavior wise.

While we do not advocate using natural alternatives over traditional medications, learning more about supporting your cat’s immune system can help devise a lifelong healthy strategy. Amoxicillin for cats has many benefits, some side effects and should always be taken as directed by a professional vet. Communicating closely with your veterinarian is the best way to ensure your cat’s amoxicillin treatment is doing the trick to ensure his path to health and well-being.

Follow up — although that “5 mg per pound of body weight per day” is at the absolute low end for recommended dosage — most vets would likely recommend at least twice a day for that dosage, unless there was some other co-morbidity involved.

The link to VetInfo regarding amoxicillin states that it’s OK to give to cats.

From the article:
” The human antibiotics that are suitable for use in felines include:

“Amoxicillin, used to fight bacterial infections; the dosage should be 5 mg per pound of body weight per day
“Ampicillin, employed for bacterial infections; the cat requires 10 mg per pound every 6 hours
“Tetracycline, effective against bacterial infections; the dose is 10 mg per pound every 8 hours”

Yes, VetInfo states that human amoxicillin is safe for cats, and getting him to a vet would require getting him into a carrier — which is not possible. It took 2 months of diligence just to get him positioned under a gigantic drop cage in order to get him neutered/vaccinated.

He got in a fight and developed a huge abcess. Even the feral organization that helped us get him that drop cage advised giving him amoxicillin, 50 mg, twice a day. It seems to be working.

Hi,my cat has what’s known as rodent ulcers on his lips. I rang the vet for info on what to do without bringing him in (example home remedies like bathing in salt water and metacam) she did say he may need an anti biotic if this doesn’t work. Hence no luck with home remedies I have some amoxcillon here wich is prescribed for cats it says to give point 5 grams wich I have done in syringe form just wondering what is the full cycle for this antibiotic. ?

My cat has been overridden with fleas, i cleaned him up a lot but still a few stragglers. 3 days ago i put that dosage of pet armour on him along with getting rid of the fleas, still monitoring. My vet is unable to see him until late tomorrow i asked if an antibiotic would work & they said “possible” so i p.u. Augmentin & just gave him 1cc/1.0Ml (actually just a lil less) i need your opinion also, please

I agree. Even the first heading states “Let’s look at why cats need it in the first place, the correct dosage, potential side effects and more.” yet there isn’t a single line anywhere regarding what the correct dosage is (5-10mg/lb every 12 or 24 hours for 7-10 days according to the insert in my package of amoxicillin if anyone needs it).

Totally Agreed, I help stray cats all the time and if I took each one of them to the vet I would go broke. I live in a farming community and everyone treats their own animals if they know whats wrong with them, if they don’t they put out the money and call a vet. Veterinary care is a minimum of $300 to check for a upper respiratory infection, with xrays and blood work and all they do.. Of course if your cat is not eating or lethargic you should rush to a Vet right away but if its a runny nose and a cough I think its ok to try to treat yourself. We have the internet now and so information is a keystroke away, not like the old days where you had no choice but to go to a professional for everything. Love to all…Kitten